Percussive tool



June 26, 1962 H. H. TOWNSHENDY, JR

PERCUSSIVE TOOL 2 Sheets-Sheet 1 Filed Aug. 11, 1960 INVENTOR ATTORNEYS H. H. TOWNSHEND, JR 3,040,711

June 26, 1962 PERCUSSIVE TOOL 2 Sheets-Sheet 2 Filed Aug. 11, 1960 INVENTOR Hem l1 H. 75wr7shend Jr.

Q a 6 ATTORNEY5 This invention relates to percussive tools and relates more particularly to a type of tool which, while not limited thereto, is particularly useful for stunning cattle preparatory to slaughtering them.

One object of the invention is to provide a percussive tool with improved operating principles and which is well suited for the purpose of stunning cattle.

Another object is to provide such a tool with improved actuating means.

Still another object is to provide in such a tool an improved piston structure.

Further objects of the invention be apparent from the following detailed description of one embodiment of the invention shown in the drawings by way of example.

. In the accompanying drawings:

FIG. 1 is a longitudinal elevational view of a percussive tool embodying the invention, illustrating the tool partially insection;

FIG. 2 is a fragmentary view similar to FIG. 1, showing parts of the tool in different positions; I

FIG. 3 is an enlarged sectional view taken on line 3-3 of FIG. 1;

FIG. 4 is a sectional view taken on line 44 of FIG. 1;

FIG. 5 is a sectional view taken on line 5-5- of FIG. 1; and

FIG. 6 is a sectional view taken on line 6-6 of FIG. 2.

In the drawings the valve housing of the percussive tool is indicated generally at 10, the housing being elongated and having longitudinally spaced-apart pistol grip portions 11 and 12. An air hose 13 for the supply of air under pressure is provided with a nipple l4- threaded into the butt of the pistol grip portion 11. The last-named butt is provided with a bore 15 in communication with the air hose 13 and communicating also with an outlet port 16. A valve 17 is disposed in the bore 15 to control the port 16 and is spring biased to the closed position thereof, the valve having an actuating stem 17 A trigger 18 cooperates with the last-mentioned stem to open-the valve 17. The trigger 18, which is formed as a generally L-shaped lever, is pivoted to the pistol grip portion 11 near the junction of the arms of the lever, as at 19, and has an arm 20 extending into a recess in the portion 11 to cooperate with the stem 17 of the valve. The trigger 18 is spring biased in a direction to render it inoperative. When the trigger is grasped and pressed, the valve 1.7 is opened to permit air to escape through the port 16 into an air passage 21. In open communication with the air passage 21 is an air passage 22 extending lengthwise of the valve housing.

The forward end of the valve housing It) is provided with a relatively large socket 23 through the bottom of which air may pass from the passage 22. Forwardly of the valve housing, the percussive tool is provided with a cylinder formed by a tubular part 24-, the tubular part at its rear extremity being externally threaded. The socket 23 in the forward end of the valve housing is internally threaded in part to cooperate with the threads of the last-mentioned end of the tubular part, as shown in FIG. 1. As shown in the last-mentioned view, the lower axial wall portion of the socket 23 is longer than the tates i tent cylindrical wall'of the upper axial wall portion of the socket. The reason for this will appear hereinafter. A piston, indicated generally at 25, is freely slidable in the cylinder formed by the tubular part 24-, and the piston cooperates with the hammer element, indicated generally at 26, extensible from the other end of the tubular part. The cylindrical wall of the tubular part 24 is provided with two diametrically opposite longitudinal slots 27 of substantial length. These slots terminate a distance forwardly from the last-mentioned threaded end of the tubular part 24 and have their other ends arranged a distance rearwardly from the other end of the part 24, as shown in FIGS. 1 and 2.

The aforementioned air passage 22 at its forward extremity is somewhat enlarged, as at 28, and this enlargement is threaded in part to threadedly receive a bushing 29 which restricts the passage. The rear end'of the bushing provides a seat for a valve 30 which is T-shaped in longitudinal cross section. The stem of the valve 30 extends loosely through the bushing 29 in a forward direction.

Within the rear end of the cylinder 24, there is pro vided a gasket 31 to inhibit the escape of air forwardly around the piston 25 when the latter is in the rearmost position thereof shown in FIG. 1. The gasket 31, which may be generally of funnel shape, is formed of resilient rubber-like material and is so arranged that the taper of the gasket is forwardly and inwardly, as shown in FIG. 1. A split ring 32 holds the gasket in the rear end of the cylinder, the ring occupying the rear portion of the funnel-like gasket and bottoming in the socket 23. The arrangement of the gasket 31 is such that when the piston 25 is in its rearmost position, the gasket has sealing engagement with the rear face of the piston.

The piston is'releasably locked in itsrearmost position by a mechanism intficated generally at 33 associated with the pistol grip portion 12. of the valve housing. The piston 25 is notched or recessed as at 34 to cooperate with the latch mechanism 33 which is extensible through the wall of the cylinder into the recess 34 for latching engagement with the rear Wall of the latter. The piston is provided with two diametrically opposite hand grip portions 35. The hand grip portions 35 may be dome-shaped and knurled, the portions 35 being interconnected and fixed to the piston by a pin 36 (FIG. 5) extending through the forward portion of the piston in fixed relation thereto. The hand grip portions 35 may be secured to the pin by being threaded thereon. The pin 36, of course, extends through the slots 27 in the cylinder 24, and the pin 36 prevents rotative movement of the piston through cooperation of the pin with the means defining the last-named slots.

At the forward extremity thereof, the piston 25 is provided with a boss 36 for impact on the hammer element 2 3. The rear end of the piston 25 is recessed, as by a bore 37, to provide a pressure chamber, and an apertured disk is disposed at the rear extremity of the piston over the recess or bore 37 and seated in a counterbore, the disk being indicated at 38. As shown in FIG. 1, the disk 38 is flush with the rear face of the piston and the disk is fixed to the piston by a central stem threaded in the piston, the stem being indicated at 39. In the form illustrated by way of example, the disk is provided with three round apertures, but it will be understood from the following explanation of the operation of the percussive tool that more or less apertures may be provided in the disk 38.

The apertured disk serves the function of restricting the rearward escape of air from the pressure chamber 37 when the piston is released for forward movement by the latch mechanism 33. The disk 38 is so constructed that the central part thereof impinges the free end of the stem of aoaovn 35 valve 30 to unseat the valve when and as the piston approaches its rearmost position.

The latch mechanism 33 includes an elongated lever 40 arranged generally lengthwise of the valve housing and having at its forward extremity an upstanding lug 41 to extend through'the. cylinder 24 for latching engagement with the rear face of the recess or notch 34 in the piston, the latch lever 40 being pivoted at its rear end, as at 4-2, in the pistol grip portion 12. This pivotal mounting is in a recess 43 which loosely receives the rear end of the lever 40, the arrangement being such that the latch lever may swing in a vertical plane. A helical compression spring 44 is provided having one end thereof engaging the lever 40 intermediate the ends thereof to constantly urge the lever in an upward direction. The spring 44 is housed in a bore 45 extending upwardly in the pistol grip portion 12, and the other end of the spring 44 engages a plug 46 closing the lower end of the bore 45. Forwardly of thespr ing 44, the latch lever 40 is provided with a vertical opening '47 receiving a triggermemberqi pivoted in the opening 47 as'at 49. The member 48 is, in effect, a cam and has an inclined upper rear face portion 50 for camrning engagement with the external surface of the axially longer wall portion of the socket 23. The arrangement is such that when 'the trigger member 48 is grasped and pressed in a rearward direction, the .cam surface 50 of the trigger member earns the forward end of the latch lever 40 downwardly to withdraw the lug 41 from the latching recess or notch 34 and release the piston. A cross pin 40 is carried by the latch lever 40 to be impinged by the forward face ofthe trigger member 48 to limit forward swinging movement of the last-mentioned member. 7

The hammer element 26, which is struck by the piston 25, includes a plug member 51 having a rearwardly proiecting boss 52. for engagement by the boss 3650f the piston. For reasons which will appear hereinafter, it is desirable to have the plug '51, which is .slidable in the cylinder 24, provided with an air tight seal with the cylin der. To this end an O-ring 53 maybe seated in an annu lar groove in the plug member 51. The hammer head is of bolt-like shape and preferably has a domed striking part 54 and a stem part 55 threaded centrally into the plug member 51. The stem part 55 is slidable in a bushing 56'threaded into the outer end of the cylinder 24. To secure the bushing from axial dislocation in an outward direction, a flange 57 is provided, the flange being threaded on the exterior of the cylinder'24. The fiange 57 has an annular radially inwardly: extending part 58 for engagement with a forwardly facing annular shoulder 59 provided on the bushing 56. I

Near the forward extremity of the cylinder rearwardly of the flange 57, the cylinder is provided with a plurality of circumferentially spaced bleed holes 69 for air. When the hammer element 26 is in its rearmost position, the O-ring 53, carried by the plug member 51, occupies a position rearwardly of the bleed holes 6i), and the arrangement is such that when the hammer ele-' merit is in the last-mentioned position, ambient air may enter the forward end of the cylinder 24 through the holes 6%. It may be noted'that the bushing 56 is provided with a gasket 61 closely embracing the stem part of the hammereler'nent to inhibit the escape of air in a forward direction around the stem part 55. As indicated in FIGS. 1 and 2, the hammer head may have a tapered part 62 toseat in a complemental recess formed in the forward face of the bushing 56 and limit rearward movement of the hammer element.

It is believed that the operation of the tool will be manifest from the foregoing description of its construction. When it is desired to effect a blow, as to stun an animal preparatory to slaughtering it, the trigger 18 is first pressed rearwardly to open thervalve 17 and admit air under pressure to the pressure chamber 37 in the piston 25. During this operation the piston is held in its rearmost 24, but

position by the latch mechanism 33 and the valve 30 is maintained in open position through the engagement of the pistonwith the valve. After an instant or two, the trigger '18 may be released. The percussive tool is then loaded.

The hammer head of the tool may then be thrust against the head of an animal to be stunned and the latch mechanism 33 released by pressing the trigger member 48 rearwardly. it will be understood that the loading operation and the firing operation may be eifected with the use of two hands, that is, with one hand gripping the pistol grip portion 11 and the other gripping the pistol grip portion 12. When the piston 25 is released by actuation of the trigger member 48, the air pressure in the chamber 37 drives the piston forwardly and air in the chamber 37 escapes through the restrictions in the rear of'the piston. This jet action effects a very forceful blow of the piston on the hammer element 26 to drive the latter outwardly with great force and stun the animal. However, air trapped in the forward end of the cylinder 24 by movement of the plug member 51 past the bleed holes 60, tends to cushion the hammer element to the extent that striking of the bushing 56 by the plug member 51 is inhibited. This, of course, is highly advantageous because it reduces wear on these parts. and reduces the danger of breakage of the tool. It will be understood that prior to firing the piston, the hammer element may be moved to the rearmost position thereof shown in FIG. 1, by pressing the hammer element against the head of the animal. However, air compressed in the outer end of the cylinder by the plug or plunger 51, as the latter is moved outwardly in the cylinder by the piston, tends to return the hammer element to its firing position, and this is highly advantageous. Also, the rearward movement of the hammer element, effected by air trapped in the outer end of the cylinder, tends to move the piston rearwardly toward its firing position.

To render the tool ready for the next stunning operation, the piston 25 is moved rearwardly to its firing position through the hand grip portions '35. It will be understood that the piston may be moved rearwardly very easily after the tool has been fired as the air behind the piston escapes from the cylinder through the slots 2'7 formed therein as the rear of the piston passes the rear extremities of the slots on its movement toward the hammer element. When the piston is again in its rearmost position, the latch mechanism re-engages it to hold it in position until the tool is again tired. it will be understood from the foregoing that the valve 3% may not be closed while the piston is in its rearmost position. The valve 36 is provided largely to prevent the escape of air from the tool when a piston is in a forward position and. the trigger 18 controling the valve 17 is inadveitently pressed. Actuation of the trigger is when the piston is in a forward position, effects closing of the valve 30 to prevent the escape of air from the tool. This may be important if the tool is operated from a portable source of air pressure, such as an air bottle having a limited volume.

In accordance with the foregoing disclosure, it will be appreciated that there is provided a percussive tool having improved operating principles and which is well suited for the purposes of stunning animals preparatory to slaughtering them. But it will be further understood, as previously pointed out, that the tool is not restricted to such a use. The tool may be easily supported in the two hands of the operator and may be easily loaded and fired. The hammer element and the piston of the tool may be easily and quickly moved to their firing positions. Furthermore, the tool includes improved and simplified trigger or latch mechanisms. Still further the cylinder may be easily disassembled from the valve housing and the piston and the hammer element may be easily disassembled from the cylinder. In operation, it has been found that the percussive tool delivers a very hard blow.

Still another advantage of the tool is that it is 'constructed of comparatively few and simple parts.

While only one form of the percussive tool has been shown in the drawings and described above, it will be apparent to those versed in the art that the percussive tool may take other forms and is susceptible of various changes in details without departing from the principles of the invention and the scope of the claims.

What I claim is: 1

1. In a percussive tool, a casing, means on the casing providing an outwardly extending cylinder, the casing having fluid passage means extending to the inner end of the cylinder from an air inlet in the casing to carry motive fluid, a hammer element slidable in the outer end of the cylinder and extensible a limited distance from the latter, a piston slidable in the cylinder inwardly of the hammer element and engageable with the latter to drive it, and means on the casing and extensible into the cylinder to engage and releasably latch the piston in an inner firing position, the piston having a pressure chamber in the inner end thereof provided with an inward restricted opening in communication with the cylinder to give the piston a jet action when the chamber is loaded with fluid under pressure and subsequently fired by release of the latch means, the cylinder being provided with vent means for escape of the motive fluid as the piston travels outwardly in the cylinder, the piston having means extending through the cylinder wall to be grasped for moving the piston to its inner position.

2. In a percussive tool, a casing, means on the casing providing an outwardly extending cylinder, the casing having fluid passage means extending to the inner end of the cylinder from an air inlet in the casing to carry motive fluid, manually operable valve means in the casing controlling said fluid passage means, a hammer element slidable in the outer end of the cylinder and extensible a limited distance from the latter, a piston slidable in the cylinder inwardly of the hammer element and engageable with the latter to drive it, and means on the casing and extensible into the cylinder to engage and releasably latch the piston in an inner firing position, the piston having a pressure chamber in the inner end thereof provided with an inward restricted opening in communication with the cylinder to give the piston a jet action when the chamber is loaded with fluid under pressure by operation of said valve means and subsequently fired by release of the latch means, the cylinder being provided with vent means for escape of the motive fluid as the piston travels outwardly in the cylinder, the piston having means extending through the cylinder wall to be grasped for moving the piston to its inner position.

3. In a percussive tool, elongated means forming a valve housing and a cylinder extending outwardly from the housing, said means having two longitudinally spaced apart pistol grip portions, the housing having a fluid passage extending to the inner end of the cylinder from an air inlet in the housing to carry motive fluid, manually operable valve means in the housing controlling the fluid passage and having an actuating part associated with one of said grip portions, a hammer element slidable in the outer end of the cylinder and extensible a limited distance from the latter, a piston slidable in the cylinder inwardly of the hammer element and engageable with the latter to drive it, and manually operable latch means extensible into the cylinder to engage and releasably latch the piston in an inner firing position and having an actuating part associated with the other grip portion, the piston having a pressure chamber in the inner end thereof provided with an inward restricted opening in communication with the cylinder to give the piston a jet action when the chamber is loaded with fluid under pressure by openation of said valve means and subsequently fired by release of the latch means, the cylinder being provided intermediate of its ends with vent means for escape of the motive fluid as the piston travels outwardly in the 6 cylinder, the piston having means extending through the cylinder wall to be grasped for moving the piston to its inner position.

4. In a percussive tool, elongated means forming a valve housing and a cylinder extending outwardly from the housing, said means having two longitudinally spaced apart pistol grip portions, the housing having a fluid passage extending to the inner end of the cylinder from an air inlet in the housing to carry motive fluid, manually operable valve means in the housing controlling the fluid passage and having an actuating part associated with one of said grip portions, a hammer element slidable in the outer end of the cylinder and extensible a limited distance from the latter, a piston slidable in the cylinder inwardly of the hammer element and engageable with the latter to drive it, manually operable latch means extensible into the cylinder to engage and releasably latch the piston in an inner firing position and having an actuating part associated with the other grip portion, the piston having a pressure chamber in the inner end thereof provided with an inward restricted opening in communication with the cylinder to give the piston a jet action when the chamber is loaded with fluid under pressure by operation of said valve means and subsequently fired by release of the latch means, the cylinder being provided intermediate of its ends with vent means for escape of the motive fluid as the piston travels outwardly in the cylinder, and a valve controlling the exit of said passage into the cylinder and engaged by the piston to be held open by the latter when the piston is in the inner position thereof, the last-named valve being responsive to fluid pressure 'in said passage to close when disengaged with the piston.

5 In a percussive tool, elongated means forming a valve housing and a cylinder extending outwardly from the housing, said means having two longitudinally spaced apart pistol grip portions, the housing having a fluid passage extending to the inner end of the cylinder from an air inlet in the housing to carry motive fluid, manually operable valve means in the housing controlling the fluid passage and having an actuating part associated with one of said grip portions, a hammer element slidable in the outer end of the cylinder and extensible a limited distance from the latter, a piston slidable in the cylinder inwardly of the hammer element and engageable with the latter to drive it, manualy operable latch means extensible into the cylinder to engage and releasably latch the piston in an inner firing position and having an actuating pant associated with the other grip portion, the piston having a pressure chamber in the inner end thereof provided with an inward restricted opening in communication with the cylinder to give the piston a jet action when the chamber is loaded with fluid under pressure by operation of said valve means and subsequently fired by elease of the latch means, the cylinder being provided intermediate of its ends with vent means for escape of the motive fluid as the piston travels outwardly in the cylinder, and a valve controlling the exit of said passage into the cylinder and engaged by the piston to be held open by the latter when the piston is in the inner position thereof, the last-named valve being responsive to fluid pressure in said passage to close when disengaged with the piston, the piston having means extending through the cylinder wall to be grasped for moving the piston to its inner position.

6. In a percussive tool, elongated means forming a valve housing and a cylinder extending outwardly from the housing, said means having a fluid passage extending to the inner end of the cylinder from an air inlet in the housing to carry motive fluid, a hammer element slidable in the outer end of the cylinder and extensible a limited distance from the latter, a piston slidable in the cylinder inwardly of the hammer element and engageable with the latter to drive it, and latch means on the first-named means and extensible into the cylinder to engage and re- 7 leasably latch the piston in an inner firing position, the latch means being manually operable to release the piston after the inner end of the cylinder has been filled by the motive fluid, the cylinder being provided with vent means for escape of the motive fiuid as the piston travels outwardly in the cylinder, the piston having means extending [through the cylinder wall to be grasped for moving the piston to its inner position, the hammer element comprising a bolt'like hammer head provided with an inwardly extending stem of substantially smaller diameter than the cylinder and'slidable through 'a substantially air-tight closure at the outer end of the cylinder, the hammer element also including a plunger connected to said Stem to drive the latter upon impact of the piston on the plunger, the plunger having a substantially air-tight seal with the cylinder, and the cylinder at its outer end portion having port means in the Wall thereof, communicating with the ambient atmosphere, which is rendered out of communication with the outer end of the cylinder by outward movement of the plunger as the hammer element is driven, so that air is trapped and compressed in the outer end of the cylinder to tend to limit outward movement of the hammer element and tend to return said element.

7. In a percussive tool, a casing, means on the casing providing 'an outwardly extending cylinder, the casing having fluid passage means extending to the inner end of the cylinder to carry motive fluid from an air inlet in the casing, manually operable valve means in the casing controlling said fluid passage means, a hammer element slidable in the outer end of the cylinder and extensible from the latter a limited distance, a piston slidable in the cylinder inwardly of the hammer element and engageable with the latter to drive it, and means on the casing and extensible into the cylinder to engage and releasably latch the piston in an inner firing position, the piston having a pressure chamber in the inner end thereof provided with an inward restricted opening in communication with the cylinder to give the piston a jet action when the chamber is loaded with fluid under pressure by operation of said valve means and subsequently fired by release of the latch means, the cylinder being provided with vent means for escape of the motive fluid as the piston travels outwardly in the cylinder, the piston having means extending through the cylinder wall to be grasped for moving the piston to its inner position, the hammer element comprising a bolt-like hammer head provided with an inwardly extending stem of substantially smaller diameter than the cylinder and slidable through a substantially airtight closure, the hammer element also including a plunger connected to said stem to drive the latter upon impact of the piston on the plunger, the plunger having a substantially air-tight seal with the cylinder, and the cylinder at its outer end portion having port means in the wall thereof, communicating with the ambient atmosphere, which is rendered out of communication with the outer end of the cylinder by outward movement of the plunger as the hammer element is driven, so that airis trapped and compressed in the outer end of the cylinder to tend to limit outward movement of the hammer element and tend to return said element.

References Cited in the tile of this patent UNITED STATES PATENTS 1,490,633 Peters Apr. 15, 1924 1,665,846 Tucker Apr. 3, 1928 2,120,992 Seiden June 21, 1938 2,729,198 Faccou Jan. 3, 1956 2,855,899 Beaty Oct. 14, 1958' 2,881,738 Baker Apr. 14, 1959 2,918,337 Kapitula Dec. 22, 1959 

